Process of producing mixtures of sulfuric and nitric acids.



PATBNTBD A1311. '7, 19.08.

J. H. NIBLD. PROCESS 0F PRODUCING MIXTURBS 0F SULPURIO AND NITRIG vACIDS;-

, APLICATION FILED .APL-5. 1905.

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UNITED STATES PATENT OFFICE.

JOHN HERBERT NIELD, OF HACKENSACK, NEW JERSEY, ASSIGNOR TO GENERAL CHEMICAL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK. l

Specification of Letters Patent.

Application filed April 5, 1905. Serial No. 253,918.

Patented April 7, 190s.

mixtures of sulfuric and nitric acids such asl are used for nitrating purposes, as, for instance, in the manufacture of explosives.

The object of my invention is toproduce such mixtures in an economical manner.

The invention will be fully described here-l inafter and the features of novelty pointed' vlout in the appended claims.

5'- Reference is to be had to the accompany- .1' Y ing drawing, which illustrates, partly in seci .L vention.

tion, a plant suitablefor carrying out myin- Briefly described, my process consists in causing gaseous sulfiric anhydrid to be'abs'rbed by a mixture of strong sulfuric acid. and weak mtric acid. The process 1s carriedl out in a continuous cycle.

In the drawing, A lndicates the absorbing Ytower filled with any suitable irregularshaped material such as coke, as indicated at B.' This absorber is provided atl the top "with an inlet pipe C for the admission of the 'absorbing liquid, said inlet pipe terminating within the tower A in a distrlbuting or spraying device D. The supply to the pipe C may comefrom'a tank E, and the connection of the tank with the pipe O may be controlled by an adjustable valve F. The inlet G for 'the anhydrid gas is located at the bottom of v the absorbing tower A; the outlet H for the absorption product is also'located at the botj tom;v and at the top I may locate an outlet pipe I for the escape of any unabsorbed gases such' as nitrogen or oxygen. The roduct which flows out through the ipe 'is received in a tank which is divided into two compartments by a partition K, forming at the same time an overflow. A portion ofthe product is removed from the tank J through a pipe L into a tank M, and this portion forms the final product of the process. VA valve N may control the outiiow of the liquid from the tank J to the tank M. The other portion of the product which overflows at K is passed into a cooling tank O and is then brought Aweak nitric acid into the strong sulfuric acid.

lwill be condensed in the pi e S, the con enback tothe supply .tank E in any suitable .55 manner, as by means of a ump P. This if portion of the product which 1s brought back to the sup ly tank and to the absorption tower is di uted at any suitable point of its travel or path with weak nitric acid, continuously supplied in the proper proportion through a pipe having a regulatingva'lve f In the drawing the pipe Q is'arranged to discharge the weak nitric acid intothe'ofver iiow compartment ofthetank J, but the diluting agent might .be introduced atl any Q. other point of the path of that portionof the l product which is circulated by the pum P. consider it preferable, however, to addp the g. diluent before the liquid is.` cooledfsince coney siderable heat isdeveloped by'pouring the It may be advisable in some cases topro-ff. vide a condenser pipe S communicatingwith" the tank J, the top'of' which is closed in case, this pi e being operi to the air at the .to and cooled'lby water circulating in a jacket.- T. Nitric acid vapors rising from the li uid sation product flowing bac into the tank J. At the beginning of tl i e rprocessthe.tpk E would be filled with a mixture ofawvneak solution of nitric acid (HNOs), say asolution'A of'about 40 de ees B., and astrong solution ofsulfuric aci (HZSO), say ofpercent. the amount of nitric acid used may be such as to bring the strength of sulfuric acid in the mixture down to 96 per cent. Then thel"V valve F would be o cned and a current of sulfuric anhydrid (S 3) would be introduced at the bottom of theabsorption tower A and 4forced upward therethrough in the usual way. The mixed solution of acids being weak is capable` of kabsorbing a large amount of sulfuric anhydrid, and by properly proportioning the amount of weak nitric acid and of sulfuric anhydrid I may secure at the\ outlet H a mixture of strong sulfuric acid and strong nitric acid. This fqrrnsthe final product received in the tank M. That por tion of the acid mixture which is returned to the supply tank E by the ump P is'diluted-in the tank J by the adclition of weak nitric acid from the pipe Q. The heat de, veloped by the absorption of theanhydrid and by the addition of thiswnit'ric acid is r'eiiioved in thewcooler O before the li uid is'dagain used to absorb the sulfuric an yino drid. When the condenser S is used, the vapors of nitric acid will be condensed to liquid form and thus returned to the tank J. When the severalvalves have been set as required for the continuous operation, the amount of dilution taking place in the tank J Will be 'ust sufficient to enable the absorbing liqui issuing at the spray D to take up the anhydrid supplied through the pipe G.

When the operation is continuous, the condition of the mixture will be constant, or approximately so, at each particular point lo the apparatus; that is, the strength of the acid mixture in the tank E will not vary, or at least not materially, and similarly, the strength of the final product in the left-hand compartment of the tank J Will be practically constant. This of course implies that the amount of sulfuric anhydrid which is absorbed by the acids mixture in the tower A, must be approximately equal to the amount of absorbed anhydrid Withdrawn at the valve N, or in other words, the rate of Withdrawal should correspond to the rate of absorption, since otherwise With the amount of outfioW and infiow equal for the supply tank E) it would not be possible to preserve a uniform composition of the mixture in the supply tank.

It will be obvious that the strength of the final roduct may be varied as desired by a suita le manipulation of the valves. The sulfuric acid contained in the final product may have a strength of from 98 to 99 per cent. if desired. The nitric acid used as diluent may be of a strength of 40 degrees B. asy above stated, but may be much weaker if desired.

The chief advantage of my invention resides in its great economy, inasmuch as by a single absorbing operation I am enabled to produce a strong mixture of nitric acid and sulfuric'acid, the proportions of which may be varied, and the fact that Weak nitric acid of any strength may. be used. The continuous character of the process is of consid-A arable practical value.

Various modifications may be made Without departing from the nature of my invention.

I claim as my invention:

1. The herein described process of producing a mixture of sulfuric and nitric acids, which consists in causing gaseous sulfuric anhydrid and a distributed or s read-out mixture of sulfuric acid and Wea nitric acid to travel in opposite directions in contact With each other, reserving a portion of the product as the final product, returning the remainder of the product to the first stage of the process to again absorb the anhydrid, and diluting such remainder on its return path With Weak nitric acid.

2. The herein described process of producing a mixture of sulfuric and nitric acids, which consists in bringing gaseous sulfuric anhydrid in contact with a mixture of sulfuric acid and Weak nitric acid, reserving a portion of the product as the final product, adding Weak nitric acid to the remainder of the product to dilute it, cooling such diluted product, and returning the cooled diluted product to the first stage of the process to again absorb the anhydrid.

3. The herein described process of producing a'mixture of sulfuric and nitric acids, which consists in bringing gaseous sulfuric anhydrid in contact with a mixture of sulfuric acid and Weak nitric acid, reserving a portion of the product as the final product, adding Weak nitric acid to the remainder of the product, condensing any nitric acid vapors Which may form upon the addition of the Weak nitric acid, and returnin such condensed vapors together With the iluted portion of the product to the first sta e of the process to again absorb the anhydri 4. The herein described process of producing a mixture of sulfuric and nitric acids, Which consists in bringing gaseous sulfuric anhydrid in contact with a mixture of sulfuric acid and Weak nitric acid, reserving a portion of the product as the final product, adding Weak nitric acid to the remainder of the product to dilute the same, condensing any nitric acid vapors which may form u on the addition of the Weak nitric acid, cooiing the diluted product and the condensed vapors returned thereto, and conveying the cooled diluted product back to the first stage of the rocess to a ain absorb the anh drid.

5. The herein (fescribed. process o producing a mixture of sulfuric and nitric acids, which consists in bringing a s rayed downwardly traveling mixture of su furic acid and nitric acid into contact With an upward stream of gaseous sulfuric anhydrid, Withdrawing a portion of the product at the bottom, returning the remainder to the first stage of the process, and diluting such re- 110 mander on its return path, With Weak nitric acl 6. The herein described process of producing a mixture of sulfuric and nitric acids, Which consists in causin a distributed or 115 spread-out mixture of su ric acid and nitric acid to travel in one driection, and a stream of gaseous sulfuric anhydrid to travel in the opposite direction and in contact With said acids mixture, to be absorbed thereby. 120

7. The herein described process of produc ing a mixture ofsulfuric and nitric acids, which consists in bringing a stream of aseous sulfuric anhydrid into contact Wit a traveling mixture of sulfuric acid and nitric 125 acid, so as to cause the anhydrid to be absorbed by said acids mixture, removing from the resulting product continuously a portion 1 ai, i

In testimony whereof, I have signed my name to this speciiication in the presence of two subscribing Witnesses. J

HN HERBERT NIELD.

Witnesses:

WILLIAM H. JENKINS, E. H. STRICKLER. 

